Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbona...Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure(NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity,enhanced capacitive adsorption behavior, and fast K+ ion diffusion kinetics. Additionally, a series of exsitu characterizations demonstrate that NSC exhibits superior structural stability during the(de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g-1 at 0.1 Ag-1 and a stable capacity of 105.2 m Ahg-1 even at 2 Ag-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs.展开更多
Smart-controlled surface wettability from superhydrophilicity to superhydrophobicity has been extensively explored,and stimulus-responsive strategies have been widely accepted as a useful method to realize reversibili...Smart-controlled surface wettability from superhydrophilicity to superhydrophobicity has been extensively explored,and stimulus-responsive strategies have been widely accepted as a useful method to realize reversibility.However,achieving smart and precise wetting control remains challenging because most previous studies focused on stimulating single surface chemistry or microstructures.Herein,a dualstimulus-responsive strategy that can synergistically stimulate surface chemistry and microstructures is demonstrated on the pH-responsive molecule poly(2-(diisopropylamino)ethyl methacrylate(PDPAEMA)-modified temperature-triggered shape memory polymer(SMP)arrays.The responsive PDPAEMA and SMP can provide the surface with tunable surface chemistry and microstructures,respectively.Thus,the wetting of the surface between various states can be reversibly and precisely controlled from superhydrophilicity to superhydrophobicity with contact angle(CA)differences of less than 15° under the cooperative effect between the adjustable surface microstructure and chemistry.The surface is further utilized as a platform to create gradient wettings based on its excellent controllability.Therefore,this work presents a strategy for surface wetting control by combining tunable surface microstructures and chemistry.The prepared samples with a special wetting controllability can be applied to numerous fields,including adaptive liquid microlenses,accurate drug release,and selective catalysis.This work also proposes novel expectations in designing smart functional surfaces.展开更多
基金supported by the National Natural Science Foundation of China (51932011, 51972346, 51802356, and 51872334)Innovation-Driven Project of Central South University (2020CX024)the Fundamental Research Funds for the Central Universities of Central South University (2020zzts075)。
文摘Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure(NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity,enhanced capacitive adsorption behavior, and fast K+ ion diffusion kinetics. Additionally, a series of exsitu characterizations demonstrate that NSC exhibits superior structural stability during the(de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g-1 at 0.1 Ag-1 and a stable capacity of 105.2 m Ahg-1 even at 2 Ag-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs.
基金supported by the National Natural Science Foundation of China(21674030,22075061 and 51790502)the Funding of Key Laboratory of Bioinspired Materials and Interfacial Science,the Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,China National Postdoctoral Program for Innovative Talents(BX20200106)。
文摘Smart-controlled surface wettability from superhydrophilicity to superhydrophobicity has been extensively explored,and stimulus-responsive strategies have been widely accepted as a useful method to realize reversibility.However,achieving smart and precise wetting control remains challenging because most previous studies focused on stimulating single surface chemistry or microstructures.Herein,a dualstimulus-responsive strategy that can synergistically stimulate surface chemistry and microstructures is demonstrated on the pH-responsive molecule poly(2-(diisopropylamino)ethyl methacrylate(PDPAEMA)-modified temperature-triggered shape memory polymer(SMP)arrays.The responsive PDPAEMA and SMP can provide the surface with tunable surface chemistry and microstructures,respectively.Thus,the wetting of the surface between various states can be reversibly and precisely controlled from superhydrophilicity to superhydrophobicity with contact angle(CA)differences of less than 15° under the cooperative effect between the adjustable surface microstructure and chemistry.The surface is further utilized as a platform to create gradient wettings based on its excellent controllability.Therefore,this work presents a strategy for surface wetting control by combining tunable surface microstructures and chemistry.The prepared samples with a special wetting controllability can be applied to numerous fields,including adaptive liquid microlenses,accurate drug release,and selective catalysis.This work also proposes novel expectations in designing smart functional surfaces.
